Refrigeration system with purging means



Oct. 4, 1966 J. A. PAPAPANU 3,27

REFRIGERATION SYSTEM WITH PURGING MEANS Filed Sept. 28, 1964 COMPRESSOR 4 COOLING WATER IN COOLER INVENTOR.

[7 JAMES A. PAPAPANU.

ATTORNEY.

United States Patent 3,276,216 REFRIGERATION SYSTEM WITH PURGING MEANS James A. Papapanu, Syracuse, N.Y., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Filed Sept. 28, 1964, Ser. No. 399,537 Claims. (CI. 6285) This invention relates to refrigeration and, more particularly, to a system and method for purging noncondensibles from a refrigeration system.

It is a primary object of this invention to provide a new and improved refrigeration system and method of providing refrigeration.

Another object is provision of a new and improved refrigeration system in which a refrigerant is circulated, with provision for purging the system of noncondensibles and including a pump for passing the noncondensibles into a separator, the pump being operable responsive to said circulation of refrigerant.

Still another object is provision of a new and improved method for purging noncondensibles from a refrigeration system and including providing cooling by circulating refrigerant to a cooler, passing the noncondensibles to a liquid and vapor separator by operation of a pump, and operating the pump by said circulation of refrigerant.

These and other objects of the invention will be apparent from the following description and the accompanying drawing which is a flow diagram of a refrigerant side of a refrigeration system incorporating a preferred embodiment of an improved purge system for removing noncondensibles from the refrigeration system.

As illustrated in the drawing, a refrigerant compressor 11 passes high pressure refrigerant vapor on a high pressure side of the system through a line 12 to a refrigerant condenser 13 from which refrigerant condensate flows through conduit means in the form of a refrigerant condensate line 14 to flow metering means, here in the form of a float valve unit 15, and then on a low pressure side of the system through a line 16 into a suitable cooler 17. The refrigerant is vaporized in the cooler as it cools chilled water passing through a chilled water line 18 including a chilled water bundle 19 within the cooler 17. Refrigerant vapor is returned from the cooler 17 to the compressor 11 through a suction line 20, for recirculation through the refrigerant side of the system, thus completing a basic refrigeration cycle. Condensing water, for example tower water, enters the system through a tower water inlet line 21 and passes through a refrigerant condensing bundle 22 in the refrigerant condenser 13, from which the tower water is returned to the tower through an outlet line 23.

Noncondensible vapors, for example air, may be present in the refrigeration system and are carried with the refrigerant vapor into the refrigerant condenser 13 where they tend to collect in the coldest portion of the refrigerant condenser, for example, where tower water enters the condenser.

In the illustrated embodiment, the noncondensibles are removed from the refrigerant condenser by means of a purge line 24 having an inlet end 25 at the inlet portion of the condensing bundle 22, and an opposite terminal end 26 connected with a pump 27 for reducing the pressure in the purge line 24 below that in the refrigerant condenser 13. Herein, the pump 27 is in the form of a jet pump connected in the refrigerant condensate line 14 for utilizing liquid refrigerant as an impelling fluid to provide a reduced pressure area at the pump throat to which the terminal end 26 of the purge line 24 is connected. From the jet pump 27, the refrigerant and noncondensibles pass into a closed liquid and vapor separator vessel 29 in which the noncondensibles collect in an upper portion 30 of the vessel above a body of liquid refrigerant in a lower portion 31 of the vessel. The liquid passes from the vessel through the condensate line 14 to the float valve 15. If desired, the upper portion of the storage vessel may contain a cooling coil connected in the tower water circuit, for example, for condensing any refrigerant vapor above the body of liquid refrigerant in the vessel. A suitable blow-off valve 31 communicates with the upper portion of the separator vessel for releasing the noncondensibles from the vessel.

In order to prevent flashing in the jet pump 27, the impeller liquid refrigerant from the condenser 13 is subcooled between the condenser and the jet pump, as by a suitable impelling fluid heat exchanger 32 which may be connected in the tower water circuit.

Some refrigerant vapor will pass with the noncondensibles through the purge line 24 from the refrigerant condenser 13. In order to remove the refrigerant vapor from the noncondensibles, a stripper or cold trap heat exchanger 33 may be provided in the purge line 4 and connected in circuit with a suitable cooling medium, as illustrated, chilled water in the leaving branch of the chilled water line 18 from the cooler 17. The refrigerant vapor condensed in the stripper heat exchanger 33 passes through a drain line 34 and into the condensate line 14 between the refrigerant condenser 13 and the impelling fluid heat exchanger 32. The drain line 34 is provided with a loop 35 for effectively preventing flow of vapor through the line.

Thus, normal refrigerant fiow in the system is utilized for purging noncondensibles from the refrigerant side of the system. Only by way of example, the refrigerant condenser 13 may operate at a temperature of F. resulting in a saturation pressure of 57 p.s.i.g., a throat pressure in the jet pump 27 of 47 p.s.i.g. and a discharge pressure from the jet pump of 52 p.s.i.g. so that the separator vessel 2? and the condensate line 14 downstream of the jet pump 27 are also at 52 p.s.i.g. The stripper heat exchange 33 in the purge line 24 may produce a 1 p.s.i.g. pressure drop so that a pressure differential of 9 p.s.i.g. is provided for withdrawing the noncondensibles from the refrigerant condenser 13.

While a preferred embodiment of the invention has been described and illustrated, it will be understood that the invention is not limited thereto since it may be otherwise embodied within the scope of the following claims.

I claim:

1. A refrigeration system comprising refrigeration means adapted to cool a load and including a low pressure side, a high pressure side having a refrigerant condenser, and a refrigerant condensate line between said condenser and said low pressure side adapted to pass refrigerant condensate from said condenser to said low pressure side and purge means adapted to remove noncondensible vapor from said refrigeration means and including a jet pump having an impelling fluid conduit including a throat in circuit with said condensate line, means including a separator in circuit with said condensate line downstream of said jet pump and adapted to receive the discharge from said jet pump and to separate liquid and vapor, whereby refrigerant condensate from the condenser may pass successively through said jet pump to impel the pump and then through said separator to said low pressure side of the system, said purge means including a purge line providing communication between said condenser and the throat of said jet pump and adapted to pass noncondensible vapor from said condenser to said jet pump for passage to said separator, and means adapted to release the noncondensibles from said separator.

2. A system according to claim 1 in which said refrigeration means includes refrigerant flow metering means in said condensate line between said condenser and said low pressure side of the system, and said jet pump and said separator are in said condensate line between said condenser and said refrigerant flow metering means.

3. A system according to claim 2 in which said purge line is adapted to withdraw refrigerant vapor with said noncondensible vapor, and heat exchange means in said purge line adapted to condense said refrigerant vapor.

4. A system according to claim 3 in which said heat exchange means is connected in circuit by means adapted to pass the resultant refrigerant condensate from said heat exchange means to said condensate line between said refrigerant condenser and said jet pump.

5. A system according to claim 2 in which said purge line withdraws refrigerant vapor with said noncondensible vapor, first heat exchange means in said purge line for condensing said refrigerant vapor, second heat exchange means in said condensate line between said refrigerant condenser and said jet pump for cooling the refrigerant condensate impelling said jet pump to a temperature below that of the vapor entering said jet pump through said purge line, and means for passing the refrigerant condensate from said first heat exchange means to said condensate line upstream of said second heat exchange means.

6. A system according to claim 5 in which said condensate line is in circuit adapted to pass substantially all refrigerant condensate from said condenser to said metering means.

7. A method of purging noncondensibles from a refrigeration system which provides cooling by circulation of liquid refrigerant through a refrigerant circuit, comprising passing the noncondensibles to a separator by operation of a pump, and providing the motive force of said pump by said circulation of the liquid refrigerant through said circuit, separating the noncondensibles from the liquid refrigerant in the separator, and discharging the noncondensibles from the refrigeration system.

8. A method according to claim 7 in which said refrigeration system has a refrigerant condenser in said circuit and said pump is a jet pump connected in said circuit and said noncondensible vapor is Withdrawn from said refrigerant condenser by the jet pump, and said jet pump is operated by passing said liquid refrigerant through the pump to provide impelling fluid for the pump.

9. A refrigeration system comprising means including ing a refrigerant circuit adapted to provide refrigeration for cooling a load by circulation of liquid refrigerant in said refrigerant circuit, a pump in said circuit which has the motive force for its operation provided by the circulation of liquid in said circuit, a purge unit connected to the outlet of said pump, said purge unit having means to expel noncondensibles from said circuit and means to pass noncondensibles to said pump from said refrigerant circuit so that during normal operation of said circuit noncondensibles are purged from said circuit.

10. In a method of purging noncondensibles from a refrigeration system which provides cooling by circulation of liquid refrigerant through a refrigerant circuit comprising passing the noncondensibles to a separator by operation of a jet pump providing the motive force of said pump by said circulation of the liquid refrigerant through said circuit, separating the noncondensibles from the liquid refrigerant in the separator, discharging the noncondensibles from the refrigeration system, said system having a condenser in said circuit, the jet pump being connected in said circuit, the noncondensibles being withdrawn from the condenser by the pump, the pump being operated by passing said liquid refrigerant through the pump to provide impelling fluid for the pump, refrigerant condensate being passed from the condenser to the jet pump to provide said liquid refrigerant for operating the jet pump, cooling the condensate below the temperature of the noncondensibles entering the jet pump prior to passing the condensate through the jet pump for effectively preventing flashing in the pump, withdrawing refrigerant vapor from said refrigerant condenser along with noncondensibles, cooling the withdrawn vapors to condense the refrigerant vapor, and passing the resultant condensate of said withdrawn vapor to the liquid refrigerant passing from the refrigerant condenser prior to passing the liquid refrigerant through said jet pump.

References Cited by the Examiner UNITED STATES PATENTS 2,202,010 5/1940 Kondolf 62-85 2,450,707 10/1948 Zwickl 6285. 3,013,404 12/1961 Endress et a1. 62475 X 3,138,005 6/1964 Bourne et al. 6285 3,145,544 8/1964 Weller 62-85 X ROBERT A. OLEARY, Primary Examiner. W. E. WAYNER, Assistant Examiner. 

7. A METHOD OF PURGING NONCONDENSIBLES FROM A REFRIGERATION SYSTEM WHICH PROVIDES COOLING BY CIRCULATION OF LIQUID REFRIGERANT THROUGH A REFRIGERANT CIRCUIT, COMPRISING PASSING THE NONCONDENSIBLES TO A SEPARATOR BY OPERATION OF A PUMP, AND PROVIDING THE MOTIVE FORCE OF SAID PUMP BY SAID CIRCULATION OF THE LIQUID REFRIGERANT THROUGH SAID CIRCUIT, SEPARATING THE NONCONDENSIBLES FROM THE LIQUID REFRIGERANT IN THE SEPARATOR, AND DISCHARGING THE NONCONDENSIBLES FROM THE REFRIGERATION SYSTEM. 